THIS INVENTION relates to improvements in skid-steer vehicles. In particular, the invention is directed to a compact multi-purpose skid-steer mini-loader.
There are various types of known skid-steer loaders, perhaps the most popular being that sold under the trade mark BOBCAT(trademark). The popularity of these loaders is due, at least in part, to their manoeuverability and versatility. The hydraulic skid-steer drive enables the loader to turn sharply, and eliminates the need for complex steering and gearing mechanisms. The interchangeability of the loader bucket with other tools, such as a posthole digger, trench digger, rotary sweeper, etc. enables a single machine to provide a variety of functions.
In recent years, a smaller, stand-on version of the skid-steer loader has become popular for lighter tasks and/or operation in confined places. Examples of these smaller loaders, commonly known as xe2x80x9cmini-loadersxe2x80x9d are those sold under the trade marks KANGA(trademark) (in the United States of America) and JADEN(trademark) (in Australia).
This invention relates to improvements in skid-steer vehicles, particularly, although not solely, skid-steer vehicles of the mini-loader type.
This invention therefore provides a vehicle, typically a skid-steer mini-loader, having one or more of the following improvements.
In a first improvement, the vehicle has a power plant comprising a tank serving as a reservoir for hydraulic fluid, a hydraulic pump located within the tank, and a motor (typically an internal combustion engine) mounted on top of the tank, the motor driving the pump via an upright shaft projecting into the tank.
By locating the pump within the tank, and mounting the engine on top of the tank, a very compact arrangement of engine/pump/tank is achieved. This enables the overall size of the vehicle to be minimised. In particular, the abovedescribed arrangement allows mini-loaders to be constructed of smaller size than hitherto known mini-loaders of comparable power rating.
In a second improvement, the vehicle is provided with a pivoting panel which facilitates access to the engine bay in which the power plant is located. This pivoting panel is typically the console panel, and is angled or 7-shaped, forming the rear wall and top of a cover for the power plant. By pivoting open the console panel, the engine bay is exposed, thereby facilitating insertion, removal and servicing of the engine, pump and associated components.
In a third improvement, the vehicle chassis comprises two spaced parallel side walls, typically steel plates, fixed to either side of the tank which forms the oil reservoir for the vehicle hydraulic drive system. The side walls themselves may constitute opposite side walls of the tank.
The use of the oil reservoir tank as part of the chassis enables the chassis to be constructed in compact form and reduces the amount of material required, yet still allows the chassis to have the required strength and rigidity.
According to a fourth improvement, the vehicle is provided with a lifting arm for a bucker, scoop or other attachment, the arm being generally of inverted channel configuration and having a relatively wide central web. The web forms the front face of the arm which is located at the front of the vehicle. Hence, from the front of the vehicle, the arm appears as a single wide flat plate, creating an aesthetically pleasing appearance. The flat web of the arm also protects hydraulic equipment and the bucket self-levelling mechanism (described later) which are located under the arm.
According to a fifth improvement, a self-levelling mechanism is provided in association with the bucket arm to automatically maintain the bucket or other attachment at a constant orientation (relative to the horizontal) as the arm is raised and lowered. The automatic levelling mechanism comprises a first sprocket connected to the bucket mounting plate and rotatable therewith about its pivot axis, and a second sprocket mounted on the vehicle, typically with its axis collinear the pivot axis of the bucket arm. The first and second sprockets are connected by an endless chain, which may include rigid linkages.
The second sprocket is held stationary (to maintain the bucket or other attachment at a constant orientation). That is, due to the interconnection of the two sprockets, as the bucket arm is rotated, the mounting plate sprocket is turned (slightly) by the chain connected to the (fixed) second sprocket to counteract the rotation of the first sprocket relative to the second sprocket which would otherwise occur due to rotation of the lifting arm. This maintains the bucket or other attachment at a substantially constant orientation.
A hydraulic cylinder is connected to the second sprocket for tilting the bucket/attachment as and when required. Rotation of the second sprocket by the hydraulic cylinder causes a corresponding rotation of the first sprocket, and hence, the orientation of the bucket/attachment is changed, e.g. to empty the bucket.
By utilising a chain and sprocket arrangement, the bucket levelling mechanism can be housed under the flat bucket arm (and substantially concealed from view). Unlike known bucket levelling mechanisms which comprise rigid linkages protruding above the bucket arm, the bucket levelling mechanism of this invention can be concealed under the arm.
According to a sixth improvement, a xe2x80x9cquick hitchxe2x80x9d locking mechanism is provided for mounting an attachment, such as a bucket, to a mounting plate on the arm. This mechanism includes at least one toggle arm on the rear of the mounting plate which automatically locks the attachment to the mounting plate when the mounting plate is inserted into mounting brackets on the attachment. In this manner, the attachment may be mounted and locked to the mounting plate remotely by the vehicle operator by manoeuvering the mounting plate into the mounting brackets on the attachment.
Other features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention.